RE: [Xen-devel] cdrom config change break HVM reboot

["Yu, Ke" <ke.yu@xxxxxxxxx>]

Ewan Mellor wrote:
> On Wed, Aug 23, 2006 at 11:08:42PM +0800, Yu, Ke wrote:
> 
>> Hi Christian,
>> 
>> In cset 10921 "Use xenstore to configure ioemu block devices", a
>> empty cdrom entry is added in /etc/xen/xmexample.hvm: 
>> 
>> disk = [ 'file:/var/images/min-el3-i386.img,hda,w', ',hdc:cdrom,r' ]
>> 
>> this actually breaks the HVM reboot in ia32e, since the UNAME of
>> cdrom entry is None and control panel reboot logic can not handle
>> this.  
>> 
>> When I try the following config, the reboot works.
>> 
>> disk = [ 'file:/var/images/min-el3-i386.img,hda,w',
>> 'file:/var/image/cdrom.iso,hdc:cdrom,r' ] 
>> 
>> Per my understanding, when user want to use cdrom, they should
>> specify a physical ISO file or device,  a empty cdrom entry is not
>> valid. So I suggest the follwing simple patch, how do you think?  
>> 
>> diff -r b688d4a68a3e tools/examples/xmexample.hvm
>> --- a/tools/examples/xmexample.hvm      Tue Aug 22 14:59:16 2006
>> +0100 +++ b/tools/examples/xmexample.hvm      Wed Aug 23 22:48:46
>> 2006 +0800 @@ -70,7 +70,8 @@ vif = [ 'type=ioemu, bridge=xenbr0' ]
>>  # and MODE is r for read-only, w for read-write.
>> 
>>  #disk = [ 'phy:hda1,hda1,r' ]
>> -disk = [ 'file:/var/images/min-el3-i386.img,hda,w', ',hdc:cdrom,r' ]
>> +#disk = [ 'file:/var/images/min-el3-i386.img,hda,w',
>> 'file:/var/images/cdrom.iso,hdc:cdrom,r' ] +disk = [
>> 'file:/var/images/min-el3-i386.img,hda,w' ] 
> 
> An empty CD-ROM drive seems like a reasonable thing to me.  Can we
> not just fix the reboot logic in Xend instead?
> 
> At the least, could I see the xend.log for this?
> 
> Thanks,
> 
> Ewan.

The xend.log is attached. Fixing reboot logic in Xend is also fine to me. 

root cause: uname of cdrom is ":" when domain first created. After reboot, 
uname become None since blkif.py did not generate uname for empty cdrom entry, 
which cause exception. the following patch can fix this issue: 

diff -r b688d4a68a3e tools/python/xen/xend/server/blkif.py
--- a/tools/python/xen/xend/server/blkif.py     Tue Aug 22 14:59:16 2006 +0100
+++ b/tools/python/xen/xend/server/blkif.py     Thu Aug 24 10:12:15 2006 +0800
@@ -107,7 +107,7 @@ class BlkifController(DevController):
             if dev_type:
                 dev += ":" + dev_type
             result.append(['dev', dev])
-        if typ and params:
+        if typ and params or ":cdrom" in dev:      # allow empty cdrom
             result.append(['uname', typ + ":" + params])
         if mode:
             result.append(['mode', mode])

Best Regards
Ke

Attachment: xend.log
Description: xend.log

Attachment: reboot.patch
Description: reboot.patch

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